I’m terrified of losing my memory. Genetically, it feels almost inevitable. My mom’s family has a history of Alzheimer’s disease, while my dad’s family has a history of brain tumors. Both sides also had members who struggled with alcoholism—another indicator of poor brain health in old age.

The local edition Walk to End Alzheimer’s will make its way to Cambridge, Mass., on Sept. 23. The walk is held annually in more than 600 communities nationwide and is run by the Alzheimer’s Association....